GB623295A - Improvements in or relating to machines organised for applying pressure to the bottoms of shoes - Google Patents

Abstract

623,295. Shoe-bottom presses. BRITISH UNITED SHOE MACHINERY CO., Ltd. (United Shoe Machinery Corporation). April 26, 1947, No. 11195. [Class 17 (i)] Initial relative movement of approach to workengaging and pressure applying position of a pad-box 26, Fig. 1, and a jack 30 of a shoe bottom press is produced rapidly by supplying high pressure fluid, by means of a treadle-actuated pump 118, Fig. 4, through an adjustable pressure-regulating valve 276 to a small cylinder 18 containing a piston 22. The pad-box 26 is pivoted between the arms of a yoke 24 carried by a piston 20 in a relatively larger cylinder 16, the pistons 20, 22 being connected together. The inertia of the moving parts is thereby quickly overcome with an economy of pump capacity and a saving of time in machine operation. To obtain the higher working pressure required for the pressing operation, when, due to increasing resistance of the work and the action of the pump the pressure in the cylinder 18 rises to a predetermined value, the valve 276 in response to such pressure is opened and fluid is supplied to the cylinder 16, through an adjustable pressure-reducing valve 297 in series with the valve 276, to supplement the pressure applied to any desired degree up to the pressure in the cylinder 18. A valve 236 responds to the pressure in the cylinder 18 to connect the cylinder 16 to the source of fluid pressure through the valves 276, 297 after initial pressure has been applied to the work and also permits communication between the cylinder 16 and a fluid reservoir 110 until the cylinder is connected to the pump 118, when the communication with the reservoir is cut off. The productive capacity of the machine is increased by providing it with a pair of work-pressing stations each comprising a pad-box 26, jack 30 and piston and cylinder devices 16, 18, 20, 22 supported by a cover 12 and machine housing 10. A rotary distributing sleeve valve 146 carries a ratchet 150 which is turned successively in one direction, normally in steps of equal amount, by a pawl bar 158, at each operation of the operating treadle 28, to feed the pressure fluid through a manifold 124 to operate the stations alternately. Safety mechanism, whereby the valve 146 is turned into an intermediate position to those referred to above, in which the high pressure side of the pump and both. stations are connected to the fluid reservoir 110 and starting of the pump has no effect at either station, is provided, to prevent premature movement of one of the pressure applying members 26 when the pump is restarted following a period of idleness in which both members 26 assume their lowest position under the action of gravity. A member 204 is moved, by the pressure at the outlet side of the pump, to move the pawl 158, by which the ratchet 150 is operated, into position to be operated normally on depression of the treadle 28. Exhaust pressure fluid from the large cylinder at one station is supplied to the large cylinder at the other station to minimise load on the pump. A duplex pressure gauge 340 indicates the pressures in the large and small cylinders.